A new white dwarf companion around the Δμ star GJ 3346

Bonavita, M; Fontanive, C; Desidera, S; D’Orazi, V; Zurlo, A; Mužić, K; Biller, B; Gratton, R; Mesa, D; Sozzetti, A (2020). A new white dwarf companion around the Δμ star GJ 3346. Monthly notices of the Royal Astronomical Society, 494(3), pp. 3481-3490. Oxford University Press 10.1093/mnras/staa590

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We present the discovery of a white dwarf companion at ∼3.6″ from GJ 3346, a nearby (π ∼ 42 mas) K star observed with SPHERE@VLT as part of an open time survey for faint companions to objects with significant proper motion discrepancies (∆μ) between Gaia DR1 and Tycho-2. Syrius-like systems like GJ 3346 AB, which include a main sequence star and a white dwarf, can be difficult to detect because of the intrinsic faintness of the latter. They have, however, been found to be common contaminants for direct imaging searches. White dwarfs have in fact similar brightness to sub-stellar companions in the infrared, while being much brighter in the visible bands like those used by Gaia. Combining our observations with Gaia DR2 and with several additional archival data sets, we were able to fully constrain the physical properties of GJ 3346 B, such as its effective temperature (11× 103 ±500 K) as well as the cooling age of the system (648±58 Myrs). This allowed us to better understand the system history and to partially explains the discrepancies previously noted in the age indicators for this objects. Although further investigation is still needed, it seems that GJ 3346, which was previously classified as young, is in fact most likely to be older than 4 Gyrs. Finally, given that the mass (0.58 ± 0.01 M☉) and separation (85 au) of GJ 3346 B are compatible with the observed ∆μ, this discovery represents a further confirmation of the potential of this kind of dynamical signatures as selection methods for direct imaging surveys targeting faint, sub-stellar companions.

Item Type:

Journal Article (Original Article)

Division/Institute:

10 Strategic Research Centers > Center for Space and Habitability (CSH)
08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute
08 Faculty of Science > Physics Institute > NCCR PlanetS

UniBE Contributor:

Fontanive, Clémence Cécile Pia

Subjects:

500 Science > 520 Astronomy
500 Science > 530 Physics

ISSN:

0035-8711

Publisher:

Oxford University Press

Language:

English

Submitter:

Danielle Zemp

Date Deposited:

05 May 2020 13:19

Last Modified:

05 May 2020 13:27

Publisher DOI:

10.1093/mnras/staa590

BORIS DOI:

10.7892/boris.142567

URI:

https://boris.unibe.ch/id/eprint/142567

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